In recent years, a modulation method known as an orthogonal frequency-division multiplexing (hereinafter also referred to as OFDM) method has been used as a method for transmitting digital signals. The OFDM method is a method of preparing a large number of orthogonal subcarriers within a transmission band, assigning data to amplitude and a phase of each subcarrier, and performing digital modulation by such means as phase shift keying (PSK) or quadrature amplitude modulation (QAM).
An OFDM time domain signal is transmitted in a unit of a symbol called an OFDM symbol (see Non-Patent Document 1, for example). The OFDM symbol is configured by a guard interval and an effective symbol.
By adding a guard interval, regarding a multipath shorter than the guard interval, it is possible to eliminate an influence of the multipath by performing appropriate signal processing on the side of the receiving apparatus (see Patent Documents 1, 2, and 3, for example). Due to such a characteristic, the OFDM method is often employed in digital terrestrial broadcasting that is largely susceptible to multipath interference. Examples of the digital terrestrial broadcasting employing the OFDM method include standards such as digital video broadcasting-terrestrial (DVB-T) and integrated services digital broadcasting-terrestrial (ISDB-T), for example.